Source selection criteria are the subjective and objective criteria that are used to evaluate proposals and select a supplier (seller). For a standard, simple product, the criteria could be as simple as lowest cost. For a more complex or non-standard product, it may be necessary to evaluate proposals from multiple potential suppliers on a variety of criteria to pick the best one for the project. Some potential source selection criteria are described in section 22.214.171.124 of the PMBOK 5th edition. In addition, the various criteria may be assigned weights based on their relative importance.